JP3184207B2 - Ceramic multilayer substrate and method of manufacturing the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a manufacturing method for erecting terminal pins on a ceramic multilayer substrate, and a ceramic multilayer substrate manufactured by this method.

[Prior Art] In recent years, ceramic substrates have been multi-layered in response to miniaturization and densification of electronic circuits. Attention has been paid.

As a conventional substrate material, an alumina multilayer substrate having excellent characteristics from the viewpoint of heat dissipation, thermal expansion coefficient, dimensional stability, and the like occupies an important position. However, since the firing conditions of alumina generally require a high temperature of 1500 ° C. or more, the range of use has been limited to heat-resistant metals such as Mo and W as conductive materials. In addition, since it is necessary to withstand high-temperature firing, certain restrictions have been imposed on the resistor material and the like.

In order to overcome such problems of the alumina multilayer substrate and expand the range of use of electronic components such as conductor materials and resistor materials, a substrate of sufficient quality was manufactured even at a low firing temperature of about 900 ° C. In recent years, by using several materials such as glass powder that can be fired even at 700 ° C. or less to about 1000 ° C., for example, a substrate and a conductive paste can be used as a multilayer wiring board. Low-temperature fired substrates that can be fired simultaneously have been put to practical use. In general, low-temperature fired substrates have advantages such as the ability to screen print conductors, high conductivity, and excellent high frequency characteristics.

By using such a low-temperature fired substrate, the range of use of the conductive material and the resistor material can be expanded, and a higher-performance substrate can be provided. Low-temperature fired substrates have been widely used in hybrid integrated circuits (hybrid ICs) and the like that require higher density.

In general, terminal pins for obtaining electrical connection with the outside are provided upright at predetermined positions on a ceramic substrate, but those that have been frequently used as ceramic substrates in the past are made of aluminum oxide as described above. Since the alumina substrate is fired at a high temperature of 1500 to 1600 ° C., it was not possible to attach pins to predetermined positions in advance at the stage of the green sheet before firing.

In the conventional manufacturing method, as shown in FIG. 2, a Ni plating 34 is applied to a conductor pattern 32 of a high melting point material such as W or Mo formed on the surface of an alumina substrate 30 during sintering, and the Ag / C
The terminal pins 38 coated with a brazing agent 36 such as a u-alloy are arranged and are erected by brazing. For this reason, terminal pins
The mechanical strength such as bending and pulling of 38 was not enough. In addition, when arranging the pins, since the substrate shrinks due to baking and the predetermined connection position changes, the process is complicated, such as the need to position each terminal pin.

In order to solve such a problem, the present applicant has previously filed Japanese Patent Application No. 2-194056 as a rod-shaped sheet at a predetermined position of a multi-layer or single-layer green sheet made of glass ceramic material for low-temperature firing. A method for manufacturing a low-temperature fired circuit board, characterized in that the pins are erected and then fired at a low temperature. However, when pins are erected on a ceramic multilayer substrate, the thermal expansion coefficient between the metal of the pin material and the ceramic differs, so that a gap is generated between the pins and the ceramic, and the bonding strength tends to decrease. I understand.

[Problems to be Solved by the Invention] The present invention is to improve a ceramic multilayer substrate manufactured by erecting and simultaneously firing terminal pins on a green sheet, and to obtain a coefficient of thermal expansion between metal and ceramic of the pin material. It is an object of the present invention to provide a ceramic multilayer substrate capable of improving the bonding strength by avoiding a decrease in the bonding strength caused by the generation of a gap between the pin and the ceramic due to the difference between the two, and a method of manufacturing the same.

[Means for Solving the Problems] According to the present invention, a rod-shaped Au-Pt-Ag alloy or a Ni-Cr-Al alloy is selected at a predetermined position of a green sheet made of a low-temperature firing ceramic made of a glass ceramic material. Erecting a pin made of the material, then firing at a low temperature, driving in a pin having a convex part at the time of pressing, placing a gold via conductor under the pin in advance,
A method for manufacturing a ceramic multilayer substrate characterized by co-firing at 700-1000 ° C. is provided.

Gold via conductors are gold-containing via conductors and satisfy the following conditions: At 700 to 1000 ° C, they do not deteriorate in the air and do not decrease in hardness. They are firmly bonded to the metal body that is the conductor of the substrate. It is preferable to use one that does.

Further, according to the present invention, there is provided a ceramic multilayer substrate manufactured by the above-described method.

As a low-temperature firing ceramic comprising a glass ceramic material that can be used in the present invention, for example, lead borosilicate glass
Alumina and the like can be exemplified, and sintering is preferably performed at a temperature of 700 to 1000 ° C. using such a ceramic.

The material of the pins erected on the green sheet may be a commonly used material, for example, an Au-Pt-Ag alloy or the like can be used.

The protrusion of the pin has a diameter of about 200 to 300% of the diameter of the pin.

A gold via conductor having a strong bonding property with the pin is formed below the pin having such a convex portion, and the diameter of the gold via conductor is preferably substantially equal to the diameter of the convex portion of the pin. The vertical thickness of the gold via conductor is preferably about 0.2 to 0.6 mm.

[Operation] As described above, the present applicant previously used a glass ceramic material that can be fired at a low temperature of usually 1000 ° C. or less as a ceramic material, and there was no deterioration of the pins due to firing, and the terminal pins were formed at the green sheet stage. A method for manufacturing a low-temperature fired circuit board capable of standing and firing is proposed. However, when pins are erected on the ceramic multilayer substrate, the thermal expansion coefficient between the metal of the pin material and the ceramic is different,
It has been found that a gap is formed between the pin and the ceramic, and the bonding strength tends to decrease.

The present invention is intended to solve such a problem,
In manufacturing a ceramic multilayer substrate, a pin having a projection is partially driven in at the time of pressing, a gold via conductor is previously arranged below the pin, and co-firing is performed.

That is, the present invention intends to improve the bonding strength from the structural aspect by utilizing the material properties of the gold via conductor having a strong bonding property with the pin and by forming the pin itself into a predetermined shape.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited only to the following examples.

FIG. 1 is a view schematically showing how a pin is erected on a ceramic multilayer substrate according to the present invention. As shown in FIG. 1, a bar-shaped pin 12 is erected at a predetermined position on a green sheet 10 made of a ceramic for low-temperature firing made of a glass ceramic material, and this pin has a projection 14 in a part. . This pin was driven in at the time of pressing, and a gold via conductor 16 was previously arranged under the pin. This was simultaneously fired after pressing to produce a ceramic multilayer substrate.

Lead borosilicate glass-alumina is used as the glass ceramic material, and the pin material is Au-Pt-Ag alloy or Ni-
A Cr-Al alloy was used, and firing was performed at 900 ° C by a conventional method.

The pin used had a diameter of 0.4 mm and a length of 3.0 mm. The size of the protrusion of the pin was 0.8 mm in diameter and 0.2 mm in length. The size of the gold via conductor was 0.8 mm in diameter and 0.2 mm in length.

In the obtained ceramic multilayer substrate, a decrease in bonding strength due to the generation of a gap between the pin and the ceramic was avoided, and the bonding strength was improved.

[Effects of the Invention] As described above, according to the present invention, a ceramic multilayer substrate manufactured by previously erecting terminal pins on a green sheet and firing them simultaneously is improved, so that the pin material and the ceramic can be interposed. The present invention provides a ceramic multilayer substrate capable of avoiding a decrease in bonding strength due to the generation of a gap between a pin and a ceramic due to a difference in thermal expansion coefficient between the pins and improving the bonding strength, and a method for manufacturing the same.

[Brief description of the drawings]

FIG. 1 is a view schematically showing how pins are erected on a ceramic multilayer substrate of the present invention, and FIG. 2 is a view showing how terminal pins are erected by a conventional method. 10 ... Green sheet, 12 ... Terminal pins 14 ... Protrusion, 16 ... Gold via conductor 30 ... Alumina substrate, 32 ... Conductor pattern 34 ... Ni plating, 36 ... Brazing agent 38 ... Terminal pin

Claims (3)

(57) [Claims] 1. A pin made of a material selected from a rod-shaped Au-Pt-Ag alloy and a Ni-Cr-Al alloy is erected at a predetermined position on a green sheet made of a low-temperature firing ceramic made of a glass ceramic material. After that, firing is performed at a low temperature, a pin having a convex portion is driven in at the time of pressing, and a gold via conductor is previously arranged under the pin, and 700-1
A method for producing a ceramic multilayer substrate, comprising co-firing at 000 ° C. 2. The gold via conductor satisfies the following conditions: 1. 700 to 1000 ° C., does not deteriorate in the air and does not decrease in hardness, 2. satisfactorily bonds to a metal body which is a conductor of a substrate. A method according to claim 1, wherein said method is used. 3. A ceramic multilayer substrate manufactured by the method according to claim 1.